Pricing formula

Hello! I am a first time caller and have the following dilemma :-

We have three different types of customers on 3 different pricing structures.

Firstly I would like Excel to recognize each customer and apply their pricing structure accordingly.

Secondly we have a pricing structure as per – minimum weigh 1 tonne, £120 per tonne. But my worksheet needs to show the actual weight even if it is under 1 tonne.

Thirdly we have another pricing structure as per - £145 per tonne with 1.4 tonne minimum then £110 per tonne thereafter.

The third pricing structure is easy and I’ve worked that one out!

Many thanks.